GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/h264_mp4toannexb_bsf.c Lines: 115 150 76.7 %
Date: 2020-11-28 20:53:16 Branches: 71 114 62.3 %

Line Branch Exec Source
1
/*
2
 * H.264 MP4 to Annex B byte stream format filter
3
 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
4
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16
 *
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 * You should have received a copy of the GNU Lesser General Public
18
 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21
22
#include <string.h>
23
24
#include "libavutil/avassert.h"
25
#include "libavutil/intreadwrite.h"
26
#include "libavutil/mem.h"
27
28
#include "avcodec.h"
29
#include "bsf.h"
30
#include "bsf_internal.h"
31
#include "bytestream.h"
32
#include "h264.h"
33
34
typedef struct H264BSFContext {
35
    uint8_t *sps;
36
    uint8_t *pps;
37
    int      sps_size;
38
    int      pps_size;
39
    uint8_t  length_size;
40
    uint8_t  new_idr;
41
    uint8_t  idr_sps_seen;
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    uint8_t  idr_pps_seen;
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    int      extradata_parsed;
44
} H264BSFContext;
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46
3504
static void count_or_copy(uint8_t **out, uint64_t *out_size,
47
                          const uint8_t *in, int in_size, int ps, int copy)
48
{
49

3504
    uint8_t start_code_size = ps < 0 ? 0 : *out_size == 0 || ps ? 4 : 3;
50
51
3504
    if (copy) {
52
1750
        memcpy(*out + start_code_size, in, in_size);
53
1750
        if (start_code_size == 4) {
54
397
            AV_WB32(*out, 1);
55
1353
        } else if (start_code_size) {
56
1339
            (*out)[0] =
57
1339
            (*out)[1] = 0;
58
1339
            (*out)[2] = 1;
59
        }
60
1750
        *out  += start_code_size + in_size;
61
    }
62
3504
    *out_size += start_code_size + in_size;
63
3504
}
64
65
5
static int h264_extradata_to_annexb(AVBSFContext *ctx, const int padding)
66
{
67
5
    H264BSFContext *s = ctx->priv_data;
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5
    GetByteContext ogb, *gb = &ogb;
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    uint16_t unit_size;
70
5
    uint32_t total_size                 = 0;
71
5
    uint8_t *out                        = NULL, unit_nb, sps_done = 0;
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    static const uint8_t nalu_header[4] = { 0, 0, 0, 1 };
73
5
    int length_size, pps_offset = 0;
74
75
5
    bytestream2_init(gb, ctx->par_in->extradata, ctx->par_in->extradata_size);
76
77
5
    bytestream2_skipu(gb, 4);
78
79
    /* retrieve length coded size */
80
5
    length_size = (bytestream2_get_byteu(gb) & 0x3) + 1;
81
82
    /* retrieve sps and pps unit(s) */
83
5
    unit_nb = bytestream2_get_byteu(gb) & 0x1f; /* number of sps unit(s) */
84
5
    if (!unit_nb) {
85
        goto pps;
86
    }
87
88
15
    while (unit_nb--) {
89
        int err;
90
91
        /* possible overread ok due to padding */
92
10
        unit_size   = bytestream2_get_be16u(gb);
93
10
        total_size += unit_size + 4;
94
        av_assert1(total_size <= INT_MAX - padding);
95
10
        if (bytestream2_get_bytes_left(gb) < unit_size + !sps_done) {
96
            av_log(ctx, AV_LOG_ERROR, "Global extradata truncated, "
97
                   "corrupted stream or invalid MP4/AVCC bitstream\n");
98
            av_free(out);
99
            return AVERROR_INVALIDDATA;
100
        }
101
10
        if ((err = av_reallocp(&out, total_size + padding)) < 0)
102
            return err;
103
10
        memcpy(out + total_size - unit_size - 4, nalu_header, 4);
104
10
        bytestream2_get_bufferu(gb, out + total_size - unit_size, unit_size);
105
10
pps:
106

10
        if (!unit_nb && !sps_done++) {
107
5
            unit_nb = bytestream2_get_byteu(gb); /* number of pps unit(s) */
108
5
            pps_offset = total_size;
109
        }
110
    }
111
112
5
    if (out)
113
5
        memset(out + total_size, 0, padding);
114
115
5
    if (pps_offset) {
116
5
        s->sps      = out;
117
5
        s->sps_size = pps_offset;
118
    } else {
119
        av_log(ctx, AV_LOG_WARNING,
120
               "Warning: SPS NALU missing or invalid. "
121
               "The resulting stream may not play.\n");
122
    }
123
5
    if (pps_offset < total_size) {
124
5
        s->pps      = out + pps_offset;
125
5
        s->pps_size = total_size - pps_offset;
126
    } else {
127
        av_log(ctx, AV_LOG_WARNING,
128
               "Warning: PPS NALU missing or invalid. "
129
               "The resulting stream may not play.\n");
130
    }
131
132
5
    av_freep(&ctx->par_out->extradata);
133
5
    ctx->par_out->extradata      = out;
134
5
    ctx->par_out->extradata_size = total_size;
135
136
5
    return length_size;
137
}
138
139
5
static int h264_mp4toannexb_init(AVBSFContext *ctx)
140
{
141
5
    H264BSFContext *s = ctx->priv_data;
142
5
    int extra_size = ctx->par_in->extradata_size;
143
    int ret;
144
145
    /* retrieve sps and pps NAL units from extradata */
146

5
    if (!extra_size                                               ||
147

5
        (extra_size >= 3 && AV_RB24(ctx->par_in->extradata) == 1) ||
148
5
        (extra_size >= 4 && AV_RB32(ctx->par_in->extradata) == 1)) {
149
        av_log(ctx, AV_LOG_VERBOSE,
150
               "The input looks like it is Annex B already\n");
151
5
    } else if (extra_size >= 7) {
152
5
        ret = h264_extradata_to_annexb(ctx, AV_INPUT_BUFFER_PADDING_SIZE);
153
5
        if (ret < 0)
154
            return ret;
155
156
5
        s->length_size      = ret;
157
5
        s->new_idr          = 1;
158
5
        s->idr_sps_seen     = 0;
159
5
        s->idr_pps_seen     = 0;
160
5
        s->extradata_parsed = 1;
161
    } else {
162
        av_log(ctx, AV_LOG_ERROR, "Invalid extradata size: %d\n", extra_size);
163
        return AVERROR_INVALIDDATA;
164
    }
165
166
5
    return 0;
167
}
168
169
798
static int h264_mp4toannexb_filter(AVBSFContext *ctx, AVPacket *opkt)
170
{
171
798
    H264BSFContext *s = ctx->priv_data;
172
    AVPacket *in;
173
    uint8_t unit_type, new_idr, sps_seen, pps_seen;
174
    const uint8_t *buf;
175
    const uint8_t *buf_end;
176
    uint8_t *out;
177
    uint64_t out_size;
178
    int ret;
179
180
798
    ret = ff_bsf_get_packet(ctx, &in);
181
798
    if (ret < 0)
182
400
        return ret;
183
184
    /* nothing to filter */
185
398
    if (!s->extradata_parsed) {
186
        av_packet_move_ref(opkt, in);
187
        av_packet_free(&in);
188
        return 0;
189
    }
190
191
398
    buf_end  = in->data + in->size;
192
193
#define LOG_ONCE(...) \
194
    if (j) \
195
        av_log(__VA_ARGS__)
196
1192
    for (int j = 0; j < 2; j++) {
197
795
        buf      = in->data;
198
795
        new_idr  = s->new_idr;
199
795
        sps_seen = s->idr_sps_seen;
200
795
        pps_seen = s->idr_pps_seen;
201
795
        out_size = 0;
202
203
        do {
204
3477
            uint32_t nal_size = 0;
205
206
            /* possible overread ok due to padding */
207
17385
            for (int i = 0; i < s->length_size; i++)
208
13908
                nal_size = (nal_size << 8) | buf[i];
209
210
3477
            buf += s->length_size;
211
212
            /* This check requires the cast as the right side might
213
             * otherwise be promoted to an unsigned value. */
214
3477
            if ((int64_t)nal_size > buf_end - buf) {
215
1
                ret = AVERROR_INVALIDDATA;
216
1
                goto fail;
217
            }
218
219
3476
            if (!nal_size)
220
                continue;
221
222
3476
            unit_type = *buf & 0x1f;
223
224
3476
            if (unit_type == H264_NAL_SPS) {
225
                sps_seen = new_idr = 1;
226
3476
            } else if (unit_type == H264_NAL_PPS) {
227
                pps_seen = new_idr = 1;
228
                /* if SPS has not been seen yet, prepend the AVCC one to PPS */
229
                if (!sps_seen) {
230
                    if (!s->sps_size) {
231
                        LOG_ONCE(ctx, AV_LOG_WARNING, "SPS not present in the stream, nor in AVCC, stream may be unreadable\n");
232
                    } else {
233
                        count_or_copy(&out, &out_size, s->sps, s->sps_size, -1, j);
234
                        sps_seen = 1;
235
                    }
236
                }
237
            }
238
239
            /* If this is a new IDR picture following an IDR picture, reset the idr flag.
240
             * Just check first_mb_in_slice to be 0 as this is the simplest solution.
241
             * This could be checking idr_pic_id instead, but would complexify the parsing. */
242

3476
            if (!new_idr && unit_type == H264_NAL_IDR_SLICE && (buf[1] & 0x80))
243
                new_idr = 1;
244
245
            /* prepend only to the first type 5 NAL unit of an IDR picture, if no sps/pps are already present */
246


3476
            if (new_idr && unit_type == H264_NAL_IDR_SLICE && !sps_seen && !pps_seen) {
247
28
                if (ctx->par_out->extradata)
248
28
                    count_or_copy(&out, &out_size, ctx->par_out->extradata,
249
28
                                  ctx->par_out->extradata_size, -1, j);
250
28
                new_idr = 0;
251
            /* if only SPS has been seen, also insert PPS */
252


3448
            } else if (new_idr && unit_type == H264_NAL_IDR_SLICE && sps_seen && !pps_seen) {
253
                if (!s->pps_size) {
254
                    LOG_ONCE(ctx, AV_LOG_WARNING, "PPS not present in the stream, nor in AVCC, stream may be unreadable\n");
255
                } else {
256
                    count_or_copy(&out, &out_size, s->pps, s->pps_size, -1, j);
257
                }
258
            }
259
260

3476
            count_or_copy(&out, &out_size, buf, nal_size,
261
                          unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS, j);
262

3476
            if (!new_idr && unit_type == H264_NAL_SLICE) {
263
24
                new_idr  = 1;
264
24
                sps_seen = 0;
265
24
                pps_seen = 0;
266
            }
267
268
3476
            buf += nal_size;
269
3476
        } while (buf < buf_end);
270
271
794
        if (!j) {
272
397
            if (out_size > INT_MAX - AV_INPUT_BUFFER_PADDING_SIZE) {
273
                ret = AVERROR_INVALIDDATA;
274
                goto fail;
275
            }
276
397
            ret = av_new_packet(opkt, out_size);
277
397
            if (ret < 0)
278
                goto fail;
279
397
            out = opkt->data;
280
        }
281
    }
282
#undef LOG_ONCE
283
284
    av_assert1(out_size == opkt->size);
285
286
397
    s->new_idr      = new_idr;
287
397
    s->idr_sps_seen = sps_seen;
288
397
    s->idr_pps_seen = pps_seen;
289
290
397
    ret = av_packet_copy_props(opkt, in);
291
397
    if (ret < 0)
292
        goto fail;
293
294
397
fail:
295
398
    if (ret < 0)
296
1
        av_packet_unref(opkt);
297
398
    av_packet_free(&in);
298
299
398
    return ret;
300
}
301
302
static void h264_mp4toannexb_flush(AVBSFContext *ctx)
303
{
304
    H264BSFContext *s = ctx->priv_data;
305
306
    s->idr_sps_seen = 0;
307
    s->idr_pps_seen = 0;
308
    s->new_idr      = s->extradata_parsed;
309
}
310
311
static const enum AVCodecID codec_ids[] = {
312
    AV_CODEC_ID_H264, AV_CODEC_ID_NONE,
313
};
314
315
const AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
316
    .name           = "h264_mp4toannexb",
317
    .priv_data_size = sizeof(H264BSFContext),
318
    .init           = h264_mp4toannexb_init,
319
    .filter         = h264_mp4toannexb_filter,
320
    .flush          = h264_mp4toannexb_flush,
321
    .codec_ids      = codec_ids,
322
};